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Abstract: Thrombin/antithrombin III (AT-III) proteolytic system is well known for its function in blood coagulation. Thrombin is expressed in skeletal muscle but nothing is known about the presence of AT-III in the tissue. In postmortem muscle this system has been and is still totally ignored. We therefore successfully attempted to purify AT-III from bovine skeletal muscle and characterized the purified protein (identified as AT-III by N-ter sequencing and mass spectrometry finger print) for its physicochemical and inhibitory properties. As the human blood serpin, muscle AT-III is thermolabile and stable only at alkaline pH (pH 9–10). The muscle serpin inhibits strongly thrombin in a heparin dependent manner and trypsin. Phosphatidylserine (PS) externalization demonstrated in the present work suggested that prothrombin can be activated to thrombin through binding of the activator complex on the external PS groups. PS externalization is concomitant with shrinkage of muscle fibers indicating that muscle cells are engaged in the cell death program known as apoptosis few minutes after death. We then discussed the potential role of this proteolytic system in postmortem apoptosis development as well as in the control of low voltage electrical stimulation efficiency. [Copyright &y& Elsevier]

Abstract: A new antioxidation protein named G4b was purified from Ginkgo biloba seed albumin. The results of chemical colorimetry and chemiluminescence methods showed that the hemi-inhibitory concentration (IC50) of G4b on the hydroxyl radical were 78.1μg/mL and 115.1μg/mL, and the IC50 on DPPH was 100.7μg/mL, while the IC50 on the superoxide anion and DNA injury were 23μg/mL and 27μg/mL, respectively, and the abundance of sulfur amino acids and aromatic amino acids contained in G4b might contribute to its strong antioxidation properties. G4b is a kind of homogeneous and novel protein with a molecular mass of 29,247Da, consisting of two peptides with similar molecular weights linked by a disulfide bond. Result of β-elimination reaction showed that G4b is connected with a small quantity of polysaccharide by an oxygen-glucosidic bond. [Copyright &y& Elsevier]

Abstract: To examine the purification procedure effect on the pectin amount, purity, macromolecular characteristics, and gelling ability, three pectin isolates, namely, alcohol (APP)-, dialysis (DPP)-, and metal ion (MPP)-purified pectins are obtained from acid extracts of yellow passion fruit rind using alcohol-precipitation, dialysis, or ion-binding precipitation. The results show that the amount of MPP (4.1g/100g) is significantly (p <0.05) lower than the amount of the two other pectins (6.8–7.5g/100g). In contrast, MPP has a higher galacturonic acid (78.9g/100g) and lower neutral sugar (9.7g/100g), ash (0.9g/100g), and protein (1.4g/100g) contents than the remainder (62.4–70.1, 16.0–17.8, 2.7–5.8, 3.1–3.2g/100g, respectively). Molecular-weight distribution patterns suggest that MPP is free of neutral sugar oligosaccharide contaminants unlike the others, especially APP. Therefore, the term of ‘the galacturonic acid yield’ is introduced to complement the conventional term of ‘the pectin yield’. Furthermore, MPP gel preparation is likely to set more rapidly, with the gel formed achieving a much higher strength. It is concluded that the pectin amount, composition, and physicochemical properties can be considerably affected by the purification mode. [Copyright &y& Elsevier]